The present invention relates to a self-clinching fastener that is pressable into a pre-formed hole in a component inhibiting rotation and press-out of the fastener installed in the component.
Self-clinching fasteners have been used in applications for which a fastener such as a nut, bolt, or a stud is desired to be connected to a sheet of material or other component. In certain applications, a self-clinching fastener may be pressed into a pre-formed hole in the sheet of material or other component. The fastener may include features such that the material of the component around the hole cold forms into an engagement with the fastener. However, prior self-clinching fasteners have been prone to falling out of the hole in the metal sheet when bumped or pressed by small incidental contact. This was particularly inefficient when the parts had to be moved to another location to re-install the fastener because a particular press was needed to re-install the fastener. In addition, certain prior fasteners would not consistently lock in place when installed in a metal sheet, enabling rotation of the fastener when a mating fastener was turned in engagement with the self-clinching fastener. Certain prior self-clinching fasteners could not consistently meet desired performance requirements. Rotation and press-out of prior self-clinching fasteners caused inefficiencies and increased cost in using such fasteners.
What is disclosed is a self-clinching fastener suitable for connection to a member having a shank portion of a diameter less than a head portion, the head portion having at least eight lands extending outwardly along the underside of the head portion spaced about the shank, each land having a face surface extending beyond the shank portion to a radius less than or equal to a radius of the head portion, the width of the lands reducing from adjacent the shank portion toward the radius of the head portion to mechanically interlock with a member with which the fastener is engaged when installed, and an axial annular engagement groove having a diameter larger than the shank portion, the annular engagement groove axially extending from the lands to a retaining collar adjacent the shank portion, the groove adapted to relieve material of a member on installation of the fastener by receiving material as the lands in the underside of the head portion mechanically interlock with the member.
The lands may extend to between 75% and 100% of the radius of the head portion. Alternatively, the lands may extend to between 78% and 85% of the radius of the head portion. In one alternative, the lands extend to between 90% and 100% of the radius of the head portion.
In addition, the fastener may include an annular recess on the underside of the head portion from an upper portion of the groove sloping into the head portion, and the face surface of the lands beyond the sloping annular recess being non-sloping adapted to assist in forming material into the groove as the fastener engages the member.
In one alternative, the land face surfaces are annularly angled to enable leading edge portions of the lands to initially contact material as the fastener engages the member.
The fastener may further include a plurality of partial threads along an inner portion of the groove between the retaining collar and the lands. Alternatively or additionally, edge portions of the groove and the retaining ring have serrations.
Also disclosed is a self-clinching fastener suitable for connection to a member having a shank portion of a diameter less than a head portion, the head portion having at least eight lands extending outwardly along the underside of the head portion spaced about the shank, each land having a face surface extending beyond the shank portion to a radius less than or equal to a radius of the head portion to mechanically interlock with a member with which the fastener is engaged when installed, each land having a leading edge extending toward the radius of the head portion angled from a radial plane, and an axial annular engagement groove having a diameter larger than the shank portion, the annular engagement groove axially extending from the lands to a retaining collar adjacent the shank portion, the groove adapted to relieve material of a member on installation of the fastener by receiving material as the lands in the underside of the head portion mechanically interlock with the member.
The shank portion may be threaded, and the leading edges of the lands are angled opposite the thread direction between 0 and 10 degrees.
The lands may extend to between 75% and 100% of the radius of the head portion. Alternatively, the lands may extend to between 78% and 85% of the radius of the head portion.
In addition, the fastener may include an annular recess on the underside of the head portion from an upper portion of the groove sloping into the head portion, and the face surface of the lands beyond the sloping annular surface being non-sloping adapted to assist in forming material into the groove as the fastener engages the member.
In one alternative, the land face surfaces are annularly angled to enable leading edge portions of the lands to initially contact material as the fastener engages the member.
The fastener may further include a plurality of partial threads along an inner portion of the groove between the retaining collar and the lands. Alternatively or additionally, edge portions of the groove and the retaining ring may have serrations.
In another alternative, a self-clinching fastener is disclosed suitable for connection to a member having a shank portion of a diameter less than a head portion, the head portion having at least eight lands extending outwardly along the underside of the head portion spaced about the shank, each land having a face surface extending beyond the shank portion to a diameter less than or equal to the radius of the head portion to mechanically interlock with a member with which the fastener is engaged when installed, each land face surface being annularly angled to enable portions of a leading edge of the lands to initially contact material as the fastener engages the member, and an axial annular engagement groove having a diameter larger than the shank portion, the annular engagement groove axially extending from the lands to a retaining collar adjacent the shank portion, the groove adapted to relieve material of a member on installation of the fastener by receiving material as the lands in the underside of the head portion mechanically interlock with the member. In certain alternatives, the face surface may be angled in the thread direction toward the face surface between 3 and 20 degrees.
In one alternative, each land has the leading edge extending toward the radius of the head portion angled from a radial plane. Where the shank portion is threaded, the leading edges of the lands may be angled opposite the thread direction between 0 and 10 degrees.
The lands may extend to between 75% and 100% of the radius of the head portion. Alternatively, the lands may extend to between 78% and 85% of the radius of the head portion.
In addition, the fastener may include an annular recess on the underside of the head portion from an upper portion of the groove sloping into the head portion, and the face surface of the lands beyond the sloping annular recess being non-sloping adapted to assist in forming material into the groove as the fastener engages the member.
In certain alternatives, the land face surfaces may be annularly angled to enable leading edge portions of the lands to initially contact material as the fastener engages the member.
The fastener may further include a plurality of partial threads along an inner portion of the groove between the retaining collar and the lands. Alternatively or additionally, edge portions of the groove and the retaining ring may have serrations as desired.
These and other features of the subject matter of the present application, as well as details of illustrated embodiments thereof, will be more fully understood from the following description and drawings.